Open-Source Licenses

Stockfish

Chessigma's chess analysis is powered by Stockfish, copyright the Stockfish developers, licensed under the GNU General Public License v3. In your browser we run the WebAssembly builds of Stockfish published by Nathan Rugg as Stockfish.js: the stockfish npm package version 17.1.0, and the older Stockfish 16 builds from version 16.0.0. We serve these files unmodified; they are byte-identical to those packages. The complete corresponding source code, with the build scripts, is at commit 602fd7e for 17.1.0 and tag v16.0.0 for 16.0.0. The evaluation networks come from the Stockfish project and are released under CC0; the network in the lite build we use for game review is by Linmiao Xu.

Chess libraries

• chess.js — BSD-2-Clause
• cm-chessboard — MIT
• react-chessboard — MIT